可计算的复杂桥梁特征建模技术研究*

由于缺乏有效的计算机图形学技术和三维几何建模支持，当前可计算桥梁三维几何建模面临着很大的困境。通过以下四方面的研究，建立了复杂桥梁的可计算三维特征几何模型：a）通过布尔运算，实现了任意桥梁构件基本截面的定义；b）建立了适合桥梁建模特点的曲线拉伸、渐变和构件放样等基本的三维建模方法；c）通过单元划分和节点编号策略，实现了复杂桥梁三维几何模型的构件间约束的定义；d）通过特征依赖树结合桥梁几何模型，建立了桥梁三维特征模型，并在原型系统BridgeDesign中进行了系统实现。本研究表明，根据复杂桥梁建模的专业

Research on key technologies for computable feature modeling of complicated bridge

There are several challenges and dilemmas for computable modeling of complicated bridge being lack of the effective definition between theoretical support of computer graphics and 3D gemetry model. In view of this, this paper mainly analyzed the following four aspects. Firstly, proposed data structure of arbitrary sections for bridge members by boolean operation. Secondly, put forward the basic modeling methods, such as stretch, shape morphing and element layout according to specialty characteristics of complicated bridge. Thirdly, established the methods of unit division and node numbering to create mutual constraints between different elements of complicated bridge which may help to facilitate finite element calculation of complicated bridge. Lastly, proposed feature model of bridge according to feature dependence graph. This paper indicates that design efficiency and design quality can be improved much by creating computable modeling of complicated bridge.